HYBRID YARN FOR THE FABRICATION OF FIBRE PREFORMS OF COMPOSITE PARTS, AND METHOD FOR ITS PREPARATION

摘要

A yarn is formed from discontinuous parallel fibers which are not twisted and which are held together by a covering yarn of sacrificial material wound around the fibers. The fibers comprise an intimate mixture of fibers of at least two different natures selected from carbon fibers or pre-oxidized polyacrylonitrile based carbon precursor fibers, or anisotropic or isotropic pitch based carbon precursor fibers, or phenolic or cellulosic based carbon precursor fibers, and ceramic fibers or ceramic precursor fibers. The mixture of fibers comprises, in its carbon state, at least 15% by weight of high strength fibers, having a tensile strength of at least 1500 MPa and a modulus of at least 150 MPa, and at least 15% by weight of fibers with a low Young's modulus of at most 100 GPa.